Process for quenching portland



In venl'or:

l'arney.

H. 1.-; KAISER original Filed Spt. 2o, 19:51'

E, K N I L c M m C .D N A L T R 0 D.. G N I H C N E U Q R 0 F s s E MW. R ,P

-Reimied Nev. 26, 1940 UNITED STATES PRDCESS FOR QUENCHING PORTLAND CEMENT CLmKEBS Harry E. Kaiser, Colton,

fornia Portland Cement Company, Calif., a corporation oi' California celle., wiener te ceu- Los Anxeles.

original No. 2,130,626, dated september '20, 193s,

Serial No. 164,688, September 20, 1937.

`pllcation for reissue August 19, 1940, Serial No.

14 Claims.

This invention relates generally to the manufacture of Portland cement, and has to do particularly with an improved process for rapidly quenching Portland cement clinker by means of another Portland cement clinker that is finely divided and admixed with the clinker undergoing quenching, under conditions that effect rapid and uniform cooling of the latter.

It has come to be recognized that very definite advantages, from anumbcr of standpoints, result from quenching, i. e., very rapid cooling, of Portland cement clinker. Theoretically, one object of rapid quenching of the 'clinker while it is at substantially the' clinker forming temperature, is in "freeze the equilibrium which has been set up at the clinkering temperatures among the various compounds in the clinker. Accordingly, it is desirable to quench the clinker immediately or very shortly after it passes from the clinkering n zone of the kiln. It will suiiice to state, without entering into a specific discussion of the individual compounds or their interrelationship and eil'ects under equilibrium conditions, that it has become recognized that by maintaining or freezing that equilibrium by rapid quenching, certain properties of the clinker itself, and of the finished cement, are dennitely improved.

A number of apparent advantages result from rapid quenching vof Portland cement clinker.

Quenching appears to promote ease of grindability. as indicated by the fact that the quenched clinker will be reduced to `a finer state of division when subjected to a given grinding operation, than a normally cooled or quenched clinker ground under the same conditions. lit is also indicated that the resultant clinker will have less tendency to dust." Tests indicate that cementitious or concrete mixtures containing cement made from the quenched clinker, show a materially lowered degree of expansion under the standard methods of determination.

In accordance with the invention, the hot clinker is admixed with a finely divided and relatively cool Portland cement clinker (hereinafter referred to as the quenching clinker), preferably immediately after the hot clinker leaves the clinlrering zone of the kiln, in order that the freezing effet of quenching maybe had upon the hot clinker while it is still as close as possible of five minutes.

to the kiln temperature. If desired the quenching clinker may be introduced into the discharge end of the kiln litself (commonly referred to as the nose of the kiln). Any suitable quantity or prof portion of the quenching clinker may be admixed with the hot clinker that will produce the de- -sired and proper quenching-effect. I have obtained very satisfactory results by admixing with one part of the hot clinker, around three parts by weight of the quenching clinker o a fineness passing a quarter-inch mesh screen. As indicated, these relative proportions of the admixed hot and quenching clinker may vary in accordance with other factors. as for example the temperature differential between the two materials in a given instance. In this connection it mayV be observed that the quenching clinker may be cold, or it may' be slightly heated to a temperature under say 300 F. As a general rule the proportion of quenching clinker in the admixture will be substantially in excess of the hot clinker undergoing quenching.

For the purpose of facilitating the desired rapidity and uniformity of quenching. the hot clinker and quenching clinker may be rapidly `ami intimately admixed in any suitable manner within a cooling`zone, for example in an elongated cylinder that is rotated to give continuous mixing agitation. The admixture is maintained in the cooling zone for a period of time required to drop the clinker temperature through the proper quenching range. Various factors may enter into the time element, but it may be stated, as illustrative, that ordinarily it will be desirable to cool the clinker from va temperature that may range from well above 1800 F. to as high as 2600 F., to a temperature under '700 F., within a period After the hot clinkerhas become quenched, the quenching Llinker is then separated therefrom in one or more separating or screening stages sufficient to free the quenched clinker from the quenching clinker. Absolute and complete separation may not be essential, particularly where the two clinkers have similar composition and properties, and in any eventl a small percentage of quenching clinker lines remaining in thequenched clinker will be unobjectionable. The quenched clinker may then bev ground or processed byk any of the usual methods of producing Portland cement. The separated y the invention, as shown diagrammatically Portland cement clinker by admixing relatively and in iiow sheet form in the accompanying drawing.

Portland cement clinker formed in the clinkering kiln lo is delivered by suitable means, conventionally illustrated by chute Il, into the upper end of an elongated cylindric cooler l2 that preferably is slowly rotated by suitable'means,

not shown. 'I'he iinely divided quenching clinker may be fed from a conveyor line il through line Il to be admixed with the hot clinker at the inlet end of chute Il and directly after the clinker leaves the kiln. or the quenching clinker may be taken via Aline Ii and fed into the inlet end I 2a of the cooling chamber. As illustrated. the feed end of the chamber may contain a suitable refractory lining Il. The two clinkers I are rapidly brought intoV intimate contact and subjected to thorough admixture within the rotating cooler Il. The admixture will remain in the cooler for a period of time required to quench the clinker through the proper temperature range, and ordinarily a time period of around iive to ten minutes will suilice where a ratio oi' substantially three parts of quenching clinker to one part oi'- the hot clinker is used.

The admixture maybe subjected to further cooling and further agitation to completely sep-V arate the quenching clinker from the quenched clinker, in asecond cooler II into which the rnaterialgis fed from the discharge end of cooler I2 via line Il. Cooler i1 may have one or more screen sections il through which the freed and relatively iine quenching clinker particles Vwill pass into a hopper 2li and thence into a storage bin 2|. As illustrated, the separated quenching clinker will be continuously-taken from bin 2l by way of conveyor line Il to be returned for l required for recirculation, may be combined with the quenched clinker in storage 22, as by providing :an overiiow ledge at I8 between the two proces lthat includes, quenching hot cool-iemand 'cement sunwwitn the not clinker. includes, quenching hot Portland admixing relatively clinker. land agitating the mixture while the hot clinker cools.

'clinker from the quenched 4. The process that includes, a stream of hot Portland cement clinker from the clinkering zone in a kiln, then cooling the hot clinker by admixing therewith relatively cool Portland cement clinker and subjecting the mixed clinkers to cooling in a cooling zone.

5. The process that includes, passing a stream of hot Portland cement clinker from the clinkering zone in a kiln. then cooling the hot clinker quantity ofA relatively cool Portland cement clinkerv and subjecting the mixed clinkers to cooling in a cooling zone.

passing a stream of hot Portland` Vcement clinker from the clinkering zone ina kiln to a cooling zone, yand cooling said hoi; clinker by admixing therewith a relatively cool Portland cement clinker at a point in thepathof iiow of said hot clinker between said clinkering zone and the cooling zone.

8. 'l'he process that includes, quenching hot' Portland cementgclinker by admixing relatively cool Portland cement clinker with the hot clinker, maintaining thev clinkers in intimate contact while the hot clinker cools. and separating added clinker.

9. The process that includes, quenching hot Portland cement clinker by admixing relatively cool quenching Portland cement clinker with the hot clinker, maintaining the clinkers in intimate contact while thehot clinker cools, separating A quenching clinker from the quenched clinker, and

admixing the separated quenching clinker with subsequently produced hot Portland cement clinker to quench same.

10. The process that continuously owing stream of hot Portland cement clinker by' continuously adding to and intimately admixing with the hot clinker a relatively iine and jcool Portland cement clinker, maintaining the clinker: in contact while the hot clinker cools, and then continuously separating added clinker from the quenched clinker.

11. The process that includes, continuously flowing stream of cement clinker by continuously adding to and intimately admixing ywith the hot clinker a relatively iine and cool quenching Portland cement clinker, maintaining the clinkers in contact while the hot clinker cools, then contlnuous'ly separating quenching clinker from the quenched clinker,

and continuously returning and adding separated quenching clinker to the hot clinker stream.

12. The process that includes. continuously passing a stream of hot Portland cement clinker from a clinkering zone, then quenching the hot tely and continuously introducingtoandinmatelyadmixingwiththehot clinkerstreamareiativelyiinelydividedand coolPortlandcementclinker-,andpassingthe mixture a cooling none.

13. The process that includes. passing a stream of hot Portland cemmiclinher fromaclinheringmthm includes, quenching a.

` by admixing therewith fa, comparatively larger WN. the M151' clinker by immediately and continuously introduclm;r to and intimately admixing with the hot clinker stream a relatively nely divided and cool Portland cement quenching clinker, passing the mixture through a cooling zone, and then continuously separating the quenching clinker from the quenched clinker.

14. The process that includes, continuously passing a stream'of hot Portland cement clinker lo from a clinkering zone, then quenching the hot clinker by immediately and vcontinuously introducing to and intimately admixing with the hot clinker stream a relatively finely divided and cool Portland cement quenching clinker, passing the mixture through a cooling zone, then continuously separating added quenching clinker i'rom the quenched clinker, and continuously returning and adding separated quenching clinker to the hot clinker stream.

HARRY E. KAISER.. lo 

